There are commercially available various types of powered machines for cutting and simultaneously bevelling large diameter pipes in situ. Some machines have rotary cutting tools which are advanced about the periphery of the pipe to effect the desired working action. Others use inclined torches similarly advanced both to cut and bevel metal pipes. Some rotary tool machines are powered by electricity, others are powered either by compressed air or by hydraulic fluids.
For instance, U.S. Pat. No. 1,932,462 discloses a pipe cutter which uses an electric motor to rotate a cutting tool as the cutter is displaced about the periphery of a pipe to be cut. U.S. Pat. No. 2,842,238 discloses a similarly movable tool for both cutting and bevelling pipe, the tool being powered by electricity, hydraulic fluid or compressed air. U.S. Pat. No. 2,291,395 discloses a pipe cutting machine which utilizes compressed air both to rotate the cutting tool and to drive the tool about the periphery of a pipe to be cut. U.S. Pat. No. 3,088,352 discloses a tool for use both in cutting and bevelling pipe. Various other types of machines for cutting pipe are disclosed in U.S. Pat. Nos. 3,168,002; 3,431,646; and 3,916,519.
While various commercially available and patented machines may function satisfactorily for their intended purposes, they all have certain limitations rendering them less than entirely satisfactory for cutting large diameter pipes in situ. For example, when cutting large diameter pipes it is important for the cut to be square, i.e. to be in a plane orthogonal to the longitudinal axis of the pipe. This means that when a groove, or cut, is started at one location on the periphery of the pipe it should meet precisely the other end as the rotary tool advances about the entire periphery of the pipe. Thus, anomalies in cutting accuracy can be amplified with laree diameter pipes unless the cutting machine is carefully constructed and skillfully operated.
The cutting of large diameter pipes in situ creates other problems. For instance, it is often necessary for such pipes to be cut while laying in a narrow trench which may contain water. A commercially satisfactory pipe cutting and bevelling machine must be sufficiently compact so as to be capable of being rotated about the entire periphery of the pipe often with minimal clearance between the pipe and the trench. In addition, a commercially desirable pipe cutting and bevelling machine should be capable of being readily adjusted to cut and bevel pipes of various diameters and thicknesses, should be sufficiently light in weight as to be transported readily to its point of usage, and should be capable of being connected and operated easily.